Pyrrolidinylalkylcarboxylic acid amide derivatives, their preparation and pharmaceutical compositions containing them

ABSTRACT

2-Oxo-1-pyrrolidinylalkylcarboxylic acid amides of formula I ##STR1## in which R represents a hydrogen atom or hydroxy group, R 1  represents a hydrogen atom or a methyl group and R 2  represents a substituted or unsubstituted pyridyl group or a substituted phenyl group, the substitution being by from 1 to 3 substituents, which may be the same or different selected from halogen atoms, trifluoromethyl, nitro and acetyl groups, straight or branched-chain alkyl groups having 1-4 carbon atoms, alkoxy groups having 1-4 carbon atoms, straight or branched-chain alkylmercapto groups having 1-7 carbon atoms, substituted alkylmercapto groups of the general formula II ##STR2## in which n represents 1 or 2, R 3  is a hydrogen atom or a methyl group and R 4  is a hydroxy group or an amino group of the general formula V ##STR3## in which R 8  represents a hydrogen atom or methyl group and R 9  represents a methyl group or substituted or unsubstituted benzyl group, or R 8  and R 9  together with the nitrogen atom shown in formula V, form a substituted pyrrolidine ring; sulphonyl groups of the general formula III 
     
         --SO.sub.2 R.sub.5                                         III 
    
     in which R 5  represents an --NH 2  group or an alkyl group having 1-3 carbon atoms; and aminoethoxycarbonyl groups of the general formula IV ##STR4## in which each of R 6  and R 7 , which may be the same or different, represents a hydrogen atom or methyl or ethyl group; and the pharmaceutically tolerable acid addition salts of compounds of formula I having a basic nitrogen atom are useful in treating cerebral circulatory disturbances, cerebro-atrophic crises and cerebral ageing processes.

The invention relates to new 2-oxo-1-pyrrolidinylalkylcarboxylic acid amides which exhibit valuable pharmacological properties since, inter alia, they improve the circulation of blood in the cerebral region and thus improve the supply of blood to the brain.

The compounds of the invention are of the general formula I ##STR5## in which R represents a hydrogen atom or hydroxy group, R₁ represents a hydrogen atom or a methyl group and R₂ represents a substituted or unsubstituted pyridyl group or a substituted phenyl group, the substitution being by from 1 to 3 substituents, which may be the same or different, selected from halogen atoms, trifluoromethyl, nitro and acetyl groups, straight- or branched-chain alkyl groups having 1-4 carbon atoms, alkoxy groups having 1-4 carbon atoms, straight- or branched-chain alkylmercapto groups having 1-7 carbon atoms, substituted alkylmercapto groups of the general formula II ##STR6## in which n represents 1 or 2, R₃ is a hydrogen atom or a methyl group, and R₄ is a hydroxy group or an amino group of the general formula V ##STR7## in which R₈ represents a hydrogen atom or methyl group and R₉ represents a methyl group or substituted or unsubstituted benzyl group, or R₈ and R₉, together with the nitrogen atom shown in formula V, form a substituted pyrrolidine ring; sulphonyl groups of the general formula III

    --SO.sub.2 R.sub.5                                         III

in which R₅ represents an --NH₂ group or an alkyl group having 1-3 carbon atoms; and aminoethoxycarbonyl groups of the general formula IV ##STR8## in which each of R₆ and R₇, which may be the same or different, represents a hydrogen atom or methyl or ethyl group; and the pharmaceutically tolerable acid addition salts of compounds of formula I having a basic nitrogen atom.

Examples of the substituents on the pyridyl or phenyl group are chlorine and fluorine atoms; methyl, ethyl, n-propyl, isopropyl, sec-butyl and n-butyl groups; methoxy and isopropoxy groups; methylmercapto, n-propylmercapto, isopropylmercapto, sec.-butylmercapto and n-heptylmercapto groups; 2-hydroxypropylmercapto, 3-(N,N-dimethylamino)-propylmercapto and 2-(N-methyl-N-benzylamino)-ethylmercapto groups; N-methyl-N-benzylaminoalkylmercapto groups of formula II in which the benzyl group is substituted by methoxy group(s), especially a 2-(N-methyl-N-(3,4-dimethoxybenzyl)-amino)-ethylmercapto group; 1-pyrrolidinylalkylmercapto groups of formula II in which the pyrrolidine ring of R₂ is substituted by a 2-oxo group, especially a 2-(2-oxo-1-pyrrolidinyl)-ethylmercapto group; and a 2-(N,N-diethylamino)-ethoxycarbonyl group. Conveniently the pyridyl group is unsubstituted. It will usually be attached by its 2-, 3- or 4-carbon atom to the right-hand nitrogen atom in formula I.

The new compounds of the formula I can be prepared in accordance with the invention by reacting a 2-oxo-1-pyrrolidinylalkylcarboxylic acid of the general formula VI ##STR9## in which R and R₁ have the meaning indicated above, or a reactive derivative thereof, with an amine of the formula VII

    H.sub.2 N--R.sub.2                                         VII

in which R₂ has the meaning indicated above, together with N,N'-dicyclohexylcarbodiimide in an organic solvent, e.g. chloroform, methylene chloride, tetrahydrofuran, acetonitrile or ethyl acetate, at a temperature between 0° C. and the boiling point of the particular solvent, usually 0° to 80° C. The desired compound of formula I is separated from the resultant N,N'-dicyclohexylurea.

Suitable reactive derivatives of the acids of formula VI for preparing amides, are those of a kind which are in general known, for example mixed anhydrides obtained using chloroformic acid esters, activated esters, for example nitrophenyl esters, cyanomethyl esters or trichlorophenyl esters, and acid chlorides.

The compounds of the general formula I in which R represents an OH group and/or R₁ represents a methyl group have one and/or two asymmetric carbon atoms. The invention includes these compounds in the form of racemates and optically active isomers in each case. The resolution of the racemates can be effected by processes known per se, through the formation of diastereomeric salts.

Compounds of formula I having a basic nitrogen atom, principally those having an amino-substituent as specified, form acid addition salts, which can be prepared in manner known per se from the free base.

The compounds according to the invention possess valuable pharmacological properties. They exhibit central vaso-active properties and properties for regulating metabolism and inhibiting the aggregation of thrombocytes and are suitable, above all, for the treatment of diseases of the cerebro-ischaemic and atrophic type, including organic psychosyndrome and migraine. The compounds also exhibit good tranquillising properties for many patients.

The pharmacoprophylaxis and therapy of diseases resulting from inadequate cerebral circulation, cerebroatrophic crises and cerebral ageing processes are nowadays becoming increasingly important and there has hitherto been no lack of attempts to find vasotropic compounds and compounds for regulating the metabolism which have a desirable effect on the diseases mentioned here. However, it has not been possible to achieve a decisive improvement by means of medicinal treatment with nootropic agents, central vasotropic agents and other therapeutic agents. The new active compounds now make it possible to treat these diseases.

A preferred class of compounds of the invention is those wherein R₂ represents a phenyl radical substituted by methyl radicals in the 2- and 6-positions. 2-Oxo-1-pyrrolidinylacetic acid-2,6-dimethylanilide, which combines vaso-active properties and properties for regulating metabolism which make it suitable for the treatment of cerebral circulatory disturbances, cerebro-atrophic crises and cerebral ageing processes and other cerebral affections, has been shown to be particularly effective. This is the more surprising since 2-oxo-1-pyrrolidinylacetic acid anilide, which has a similar structure and is known from British Patent Specification No. 1,039,113, exhibits none of these effects. The 2,6-dimethylanilide can easily be prepared from 2-oxo-1-pyrrolidinylacetic acid by the above-described method.

The following methods have been used to investigate the pharmacodynamic properties of the compounds according to the invention:

1. Prolongation of cerebral survival time under hypoxaemia caused by NaNO₂.

Starting from the results of Gibson and Blass (J. Neurochemistry 27, 1976), a cerebral hypoxia is produced in male mice by means of NaNO₂ (225 mg/kg, subcutaneous). The cerebral hypoxia period is marked by a characteristic spasmodic behaviour and ends in the death of the experimental animals. Measurements are made to determine whether the survival time under cerebrohypoxic conditions is significantly prolonged by premedication.

2. Prolongation of the cerebral survival time in the case of hypoxaemia caused by sub-atmospheric pressure.

It is known that animals exhibit a characteristic neuropathological behaviour if the oxygen pressure is reduced. This neuropathological behaviour is induced in male mice by a progressive reduction of the pressure to 26.66 kPa in an observation chamber and is used as an indicator of the cerebral hypoxia period. It ends in the death of the experimental animal. An investigation is made to determine whether the survival time under cerebro-hypoxic conditions is prolonged significantly by premedication.

3. Protection against amnesia induced by electric shock.

Starting from the results of Taber and Banuazizi (Psychopharmakologia 9, 1966), male mice are taught not to enter a certain compartment of the cage in order to avoid an electric shock. The response is extinguished by means of an electric shock administered via head electrodes (electric shock amnesia).

An investigation is made to determine whether the dwell time in the compartment of the cage which is free from electric shocks is significantly prolonged, as a measure of the memory of the experimental animals, by premedication.

The following commercially available compounds were used in all the tests: papaverine, cinnarizine, meclofenoxate, piracetam, vincamine, propranolol, pyritinol and 2-oxo-1-pyrrolidinylacetic acid anilide.

In the Table 1 which follows, the pharmacologically effective properties of the compounds according to the invention, determined by the experimental methods mentioned above, are compared with the commercially available compounds.

                  TABLE 1     ______________________________________                                   Sub-               Mode of             atmospheric               adminis-  NaNO.sub.2 --                                   pressure Am-     Compound  tration   hypoxaemia                                   hypoxaemia                                            nesia     ______________________________________     DZL 221.sup.1               oral      +         +        +     PA.sup.2  oral      -         -        -     Papaverine               intravenous                         +         -        -     Cinnarizine               oral      -         -        -     Meclofenoxate               oral      -         -        -     Piracetam oral      -         +        +     Vincamine oral      -         +        +     Propranol oral      +         -        +     Pyritinol oral      -         -        +     ______________________________________

As can be seen from Table 1, the compound of the invention exhibits a completely novel pattern of action in cerebral protection, since, in contrast to the known compounds, it is effective in all three test procedures.

The compound of Example 6 is highly active, well tolerated and has a very low toxicity:

LD₅₀ : 1,766 mg/kg--mice, administered orally

LD₅₀ : 421 mg/kg--mice, administered intravenously

Its excellent activity and good toleration, together with its effect of inhibiting aggregation of thrombocytes, make the compound of Example 6 outstandingly suitable for the treatment of diseases of the cerebro-ischaemic and cerebro-atrophic type, including organic pyscho-syndrome and migraine. In addition, the compound has good tranquillising properties.

The invention includes pharmaceutical compositions comprising a compound of the invention and a pharmaceutically acceptable excipient. These compositions can take any form, e.g. tablets, capsules, dragees, pills, emulsions, suspensions and solutions, using a pharmaceutically suitable excipient (which term includes a solvent or carrier).

The following are Examples of excipients which can be used: non-toxic organic solvents, such as vegetable oils (for example groundnut oil or soya oil), alcohols (for example polyethylene glycol or glycerol), solid excipients, such as, for example, ground minerals (kaolins, talc or silicates), sugars (for example lactose or glucose), emulsifiers (for example fatty acid esters or fatty alcohol ethers), dispersing agents (for example methylcellulose or starch) and lubricants (for example talc, stearic acid or cocoa butter).

Administration is usually carried out enterally using doses of 1-1,000 mg, preferably 10-100 mg, or parenterally using doses of 0.1-100 mg, particularly 1-20 mg.

The preparation of the compounds of the invention is illustrated in greater detail by means of the following Examples:

EXAMPLE 1 ##STR10## 2-Oxo-1-pyrrolidinylacetic acid 2,6-diethylanilide

22.9 g (0.16 mol) of 2-oxo-1-pyrrolidinylacetic acid C₆ H₉ NO₃ [143.1] and 23.9 g (0.16 mol) of 2,6-diethylaniline C₁₀ H₁₅ N [149.2] are heated under reflux for 4 hours in 160 ml of absolute chloroform together with 33.0 g (0.16 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated and the residue is recrystallised.

Yield: 12.4 g (28.3% of theory) C₁₆ H₂₂ N₂ O₂ [274.4]

Melting point: 195° C. (methanol/water)

EXAMPLE 2 ##STR11## 4-Hydroxy-2-oxo-1-pyrrolidinylacetic acid 2,6-dimethylanilide

19.1 g (0.12 mol) of 4-hydroxy-2-oxo-1-pyrrolidinylacetic acid C₆ H₉ NO₄ [159.1] and 14.5 g (0.12 mol) of 2,6-dimethylaniline C₈ H₁₁ N [121.2] are heated under reflux for 3 hours in 120 ml of absolute chloroform together with 24.8 g (0.12 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated in vacuo and the residue is recrystallised.

Yield: 11.5 g (36.4% of theory) C₁₄ H₁₈ N₂ O₃ [262.3]

Melting point: 159° C. (ethyl acetate/ether).

EXAMPLE 3 ##STR12## 2-[2-Oxo-1-pyrrolidinyl]propionic acid N-3-pyridylamide

36.1 g (0.23 mol) of 2-[2-oxo-1-pyrrolidinyl]-propionic acid C₇ H₁₁ NO₃ [157.1] and 21.6 g (0.23 mol) of 3-aminopyridine C₅ H₆ N₂ [94.1] are heated under reflux for 4 hours in 230 ml of absolute chloroform together with 47.4 g (0.23 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated (in vacuo) and the residue is recrystallised.

Yield: 26.0 g (48.5% of theory) C₁₂ H₁₅ N₃ O₂ [233.3]

Melting point: 108°-109° C. (ethyl acetate/diisopropyl ether).

EXAMPLE 4 ##STR13## 2-Oxo-1-pyrrolidinylacetic acid 4-isopropylmercapto anilide

14.3 g (0.1 mol) of 2-oxo-1-pyrrolidinylacetic acid C₆ H₉ NO₃ [143.1] and 16.7 g (0.1 mol) of 4-isopropylmercaptoaniline C₉ H₁₃ N₅ [167.3] are heated under reflux for 3 hours in 100 ml of absolute chloroform together with 20.6 g (0.1 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated and the residue is recrystallised.

Yield: 11.7 g (40% of theory) C₁₅ H₂₀ N₂ O₂ S [292.2]

Melting point: 128° C. (ethanol)

EXAMPLE 5 ##STR14## 2-[2-oxo-1-pyrrolidinyl]-propionic acid 4-(2-butylmercapto)-anilide

15.7 g (0.1 mol) of 2-[2-oxo-1-pyrrolindyl]-propionic acid C₇ H₁₁ NO₃ [157.1] and 18.3 g (0.1 mol) of 4-sec.-butylmercaptoaniline C₁₀ H₁₅ NS [181.3] are heated under reflux for 4 hours in 100 ml of absolute chloroform together with 20.6 g (0.1 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated and the residue is recrystallised.

Yield: 16 g (50% of theory) of C₁₇ H₂₄ N₂ O₂ S [320.4]

Melting point: 87° C. (ethanol)

EXAMPLE 6 ##STR15## 2-Oxo-1-pyrrolidinylacetic acid, 2,6-dimethylanilide

14.3 g (0.1 mol) of 2-oxo-1-pyrrolidinylacetic acid C₆ H₉ NO₃ [143.1] and 12.1 g (0.1 mol) of 2,6-dimethylaniline C₈ H₁₁ N [121.2] are heated under reflux for 3 hours in 100 ml of absolute chloroform together with 20.6 g (0.1 mol) of N,N'-dicyclohexylcarbodiimide C₁₃ H₂₂ N₂ [206.3]. After cooling, the precipitated N,N'-dicyclohexylurea is filtered off, the filtrate is concentrated and the residue is recrystallised.

Yield. 18.7 g (76% of theory) C₁₄ H₁₈ N₂ O₂ [246.3]

Melting point: 153° C. (water)

Elementary analysis: C₁₄ H₁₈ N₂ O₂ [246.3]--Calculated: C=68.27%, H=7.37%, N=11.37%, O=12.99%. Found: C=68.12%, H=7.37%, N=11.39%, O=12.94%; C=68.09%, H=7.42%, N=11.34%, O=13.09%.

IR spectrum: Instrument: Perkin-Elmer model 257 (KBr): η_(NH) :3260 cm⁻¹, η_(CO) (ring and amide) :1650-1700 cm⁻¹ (overlapping bands)

¹ H-NMR spectrum: Instrument: Hitachi Perkin-Elmer, 60 MHz, model R-24 Solvent: CDCl₃ (TMS as internal standard δ=0) NH 7.85 (s), CH_(aromatic) 7.0 (s), CH₂ 4.1 (s), CH₂ 3.6 (t), CH₂ --CH₂ 2.2 (m), CH₂ 2.1 (s).

Mass spectrum: Instrument: 311 A Varian Mat; electron energy 70eV, 200 A, temperature of source of ions 200° C., solid sample vaporisation or gas inlet for the reference substance (PFK), scanning control and recording and processing of data via a Finnigan-Incos system; M⁺ : m/e 246 (60%).

Thin layer chromatography: 60 F₂₅₄ silica gel prepared thin layer chromatographic plates (Merck)

Spraying reagent: Bromocresol Green (0.05% strength, Merck) R_(f) =0.83

Eluant: chloroform/methanol/25% strength ammonia 70:26:4 (V/V/V) R_(f) =0.36

Eluant: chloroform/methanol 90:10 (V/V)

Other compounds of formula I were prepared, and their melting points determined, analogously to the procedures of Examples 1 to 6. Table 2 lists these compounds together with those of Examples 1 and 3 to 5.

                                      TABLE 2     __________________________________________________________________________      ##STR16##                                                   Melt-                                       Empiri- Mole-                                                   ing                                       cal     cular                                                   point                                                       Yield     No. R.sub.1             R.sub.2                   formula weight                                                   °C.                                                       %     __________________________________________________________________________      1  H              ##STR17##                C.sub.13 H.sub.16 N.sub.2 O.sub.2                                               232.3                                                   134 50      2  CH.sub.3              ##STR18##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               246.3                                                   140 74      3  H              ##STR19##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               246.3                                                   150 35      4  CH.sub.3              ##STR20##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   129 81      5  H              ##STR21##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   140 30      6  H              ##STR22##                C.sub.13 H.sub.16 N.sub.2 O.sub.2                                               232.3                                                   119 36      7  H              ##STR23##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   135 56      8  CH.sub.3              ##STR24##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               274.4                                                   109 58      9  H              ##STR25##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               274.4                                                   102 28     10  CH.sub.3              ##STR26##                C.sub.17 H.sub.24 N.sub.2 O.sub.2                                               288.4                                                   110 70     11  H              ##STR27##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               274.4                                                   123 30     12  H              ##STR28##                C.sub.13 H.sub.16 N.sub.2 O.sub.3                                               248.3                                                   130 48     13  CH.sub.3              ##STR29##                C.sub.14 H.sub.18 N.sub.2 O.sub.3                                               262.3                                                   138 45     14  H              ##STR30##                C.sub.14 H.sub.18 N.sub.2 O.sub.4                                               278.2                                                   142 60     15  CH.sub.3              ##STR31##                C.sub.15 H.sub.20 N.sub.2 O.sub.4                                               292.3                                                   170 22     16  H              ##STR32##                C.sub.14 H.sub.18 N.sub.2 O.sub.4                                               278.3                                                   158 45     17  CH.sub.3              ##STR33##                C.sub.15 H.sub.20 N.sub.2 O.sub.4                                               292.3                                                   101 39     18  H              ##STR34##                C.sub.15 H.sub.20 N.sub.2 O.sub.5                                               308.3                                                   145 15     19  CH.sub.3              ##STR35##                C.sub.16 H.sub.22 N.sub.2 O.sub.5                                               322.4                                                   164 12     20  H              ##STR36##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               246.3                                                   140 30     21  CH.sub.3              ##STR37##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   120 38     22  H              ##STR38##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               246.3                                                   150 30     23  CH.sub.3              ##STR39##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   109 65     24  H              ##STR40##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               246.3                                                   146 30     25  CH.sub.3              ##STR41##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   96  26     26 (Ex. 1)         H              ##STR42##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               274.4                                                   195 28     27  H              ##STR43##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               260.3                                                   173 38     28  CH.sub.3              ##STR44##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               274.4                                                   129 42     29  H              ##STR45##                C.sub.14 H.sub.18 N.sub.2 O.sub.3                                               262.3                                                   142 35     30  CH.sub.3              ##STR46##                C.sub.15 H.sub.20 N.sub.2 O.sub.3                                               276.3                                                   114 50     31  H              ##STR47##                C.sub.14 H.sub.18 N.sub.2 O.sub.3                                               262.3                                                   134 32     32  CH.sub.3              ##STR48##                C.sub.15 H.sub.20 N.sub.2 O.sub.3                                               276.3                                                    89 54     33  H              ##STR49##                C.sub.13 H.sub.15 ClN.sub.2 O.sub.2                                               266.7                                                   144 30     34  CH.sub.3              ##STR50##                C.sub.14 H.sub.17 ClN.sub.2 O.sub.2                                               280.8                                                   134 70     35  H              ##STR51##                C.sub.13 H.sub.15 ClN.sub.2 O.sub.2                                               266.7                                                   140 35     36  CH.sub.3              ##STR52##                C.sub.14 H.sub.17 ClN.sub.2 O.sub.2                                               280.8                                                   127 58     37  H              ##STR53##                C.sub.13 H.sub.15 ClN.sub.2 O.sub.2                                               266.7                                                   142 20     38  CH.sub.3              ##STR54##                C.sub.14 H.sub.17 ClN.sub.2 O.sub.2                                               280.8                                                   103 14     39  H              ##STR55##                C.sub.13 H.sub.15 ClN.sub.2 O.sub.3                                               282.7                                                   126 40     40  CH.sub.3              ##STR56##                C.sub.14 H.sub.17 ClN.sub.2 O.sub.3                                               296.7                                                   111 35     41  H              ##STR57##                C.sub.13 H.sub.15 FN.sub.2 O.sub.2                                               250.2                                                   120 30     42  CH.sub.3              ##STR58##                C.sub.14 H.sub.15 F.sub.3 N.sub.2                                       O.sub.2 300.3                                                    82 18     43  H              ##STR59##                C.sub.15 H.sub.20 N.sub.2 O.sub.3                                               276.3                                                   142 50     44  H              ##STR60##                C.sub.19 H.sub.27 N.sub.3 O.sub.4                                               361.4                                                   117 13     45  H              ##STR61##                C.sub.14 H.sub.17 ClN.sub.2 O.sub.4                                               312.3                                                   158 55     46  CH.sub.3              ##STR62##                C.sub.15 H.sub.18 N.sub.2 O.sub.3                                               274.3                                                   168 30     47  CH.sub.3              ##STR63##                C.sub.13 H.sub.15 N.sub.3 O.sub.4                                               277.3                                                   153 10     48  H              ##STR64##                C.sub.14 H.sub.16 N.sub.2 O.sub.3                                               260.3                                                   198 65     49  CH.sub.3              ##STR65##                C.sub.15 H.sub.18 N.sub.2 O.sub.3                                               274.3                                                   165 18     50  H              ##STR66##                C.sub.13 H.sub.16 N.sub.2 O.sub.2                                               264.3                                                   140 45     51  CH.sub.3              ##STR67##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               278.3                                                   148 34     52  H              ##STR68##                C.sub.13 H.sub.16 N.sub.2 O.sub.2                                               264.3                                                   140 51     53  CH.sub.3              ##STR69##                C.sub.14 H.sub.18 N.sub.2 O.sub.2                                               278.3                                                   100 56     54  H              ##STR70##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               292.2                                                   124 30     55  CH.sub.3              ##STR71##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               306.4                                                   122 54     56 (Ex. 4)         H              ##STR72##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               292.2                                                   128 40     57  CH.sub.3              ##STR73##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               306.4                                                   142 45     58  H              ##STR74##                C.sub.16 H.sub.22 N.sub.2 O.sub.2                                               306.4                                                   110 35     59 (Ex. 5)         CH.sub.3              ##STR75##                C.sub.17 H.sub.24 N.sub.2 O.sub.2                                               320.4                                                    87 50     60  H              ##STR76##                C.sub.15 H.sub.20 N.sub.2 O.sub.3                                               308.4                                                   128 35     61  H              ##STR77##                C.sub.22 H.sub.27 N.sub.3 O.sub.2                                               397  91 30     62  H              ##STR78##                C.sub.24 H.sub.31 N.sub.3 O.sub.4                                               457.5                                                    93 28     63  H              ##STR79##                C.sub.17 H.sub.25 N.sub. 3 O.sub.2                                               335.3                                                   120 35     64  H              ##STR80##                C.sub.18 H.sub.23 N.sub.3 O.sub.3                                               361 115 22     65  H              ##STR81##                C.sub.15 H.sub.20 N.sub.2 O.sub.4                                               324.3                                                   145 35     66  H              ##STR82##                C.sub.12 H.sub.15 N.sub.3 O.sub.4                                               297.3                                                   173 40     67  H              ##STR83##                C.sub.15 H.sub.20 N.sub.2 O.sub.2                                               292.4                                                   --  15     68  H              ##STR84##                C.sub.19 H.sub.28 N.sub.2 O.sub.2                                               348.5                                                   108 30     69  H              ##STR85##                C.sub.11 H.sub.13 N.sub.3 O.sub.2                                               219.2                                                   135 40     70 (Ex. 3)         CH.sub.3              ##STR86##                C.sub.12 H.sub.15 N.sub.3 O.sub.2                                               233.3                                                   108 48     71  CH.sub.3              ##STR87##                C.sub.12 H.sub.15 N.sub.3 O.sub.2                                               233.3                                                   144 20     72  H              ##STR88##                C.sub.12 H.sub.12 Cl.sub.2 N.sub.2                                       O.sub.2 287.2                                                   162 12     73  CH.sub.3              ##STR89##                C.sub.13 H.sub.14 Cl.sub.2 N.sub.2                                       O.sub.2 301.2                                                   110 13     74  H              ##STR90##                C.sub.12 H.sub.12 F.sub.2 N.sub.2                                       O.sub.2 254.2                                                   138 11     75  CH.sub.3              ##STR91##                C.sub.13 H.sub.14 F.sub.2 N.sub.2                                       O.sub.2 268.3                                                   99  9     __________________________________________________________________________ 

We claim:
 1. 2-oxo-1-pyrrolidinylalkylcarboxylic acid amides of the general formula I ##STR92## in which R is selected from the group consisting of hydrogen and hydroxyl and R₁ is selected from the group consisting of hydrogen and methyl, and the pharmaceutically tolerable acid addition salts of compounds of formula I having a basic nitrogen atom.
 2. Compounds according to claim 1 wherein R is hydrogen.
 3. As a compound according to claim 1, 2-oxo-1-pyrrolidinylacetic acid 2,6-dimethylanilide.
 4. As a compound according to claim 1, 4-hydroxy-2-oxo-1-pyrrolidinylacetic acid 2,6-dimethylanilide.
 5. A pharmaceutical composition for the treatment of cerebral circulatory disturbances, comprising in a therapeutically effective amount at least one compound defined in any one of claims 1, 3, or 4 and a pharmaceutically acceptable excipient.
 6. A method of treating a patient for cerebral circulatory disturbance, which comprises administering to the patient a therapeutically effective dose of at least one compound defined in any one of claims 1, 4 or
 5. 